The invention relates to a driving circuit for pulse current power supplies. Such circuits are, for example, used for operating kicker magnets, which are used in electron or proton accelerators (e.g., DESY Hamburg or Fermi National Accelerator Laboratory, Batavia, Chicago) for giving the rotating electron or proton bunches the desired direction for injection or ejection with respect to the accelerator ring. This is particularly necessary at injection and ejection points of the main orbit, because the deflecting in or out of an electron or proton cannot take place precisely tangentially due to the arrangement of the beam guidance magnets. Instead, it can only be done at a small residual angle of 2.degree. to 4.degree. relative to the orbit tangent. This small residual angle can afterwards be eliminated by triggering kicker magnets which may only be active if an electron or proton bunch is just passing through the injection kicker magnets. Since the electrons are on the orbit in accelerators rotating almost with the velocity of light and packed in individual, discrete bunches, it is absolutely necessary for the kicker magnet to be excited at precisely the right time, in order to give the electron bunches the desired direction. This has hitherto only been achieved in the aforementioned circuit by using a thyratron, e.g., of type CX1154 or CX1174 of English Elektric Valve Company Ltd. A disadvantage of the known circuit is that high backward cut-off voltages which appear at the thyratron quenching time and which are only permitted to a limited extent by the manufacturer, at the end of the current pulse greatly reduce the useful current range and the lifetime of the tube. Another disadvantage is that following the desired end of the pulse current, there are still free charge carriers in the thyratron, which initially make the quenching current drop negative and then go steeply towards zero. This charge removal leads to a rapid current break di/dt of approximately 2000 A/.mu.s and therefore acts in the same way as a fast inductance coil disconnection, in which high, reverse-directed switching voltages are induced in the pulse current device. However, the cut-off voltages must not exceed a given maximum value, e.g., 10 kV for the first 25 .mu.s following the anode pulse for the desired thyratron, e.g., of type CX1154 or CX1174, because otherwise the electrical current valve will be destroyed by flashovers and arc-backs. The same applies when thyristors are used, although their limit values are different.
Thus, as the known thyratrons cannot be exposed to higher breaking or cut-off voltages than 10 kV in the reverse direction, their anode voltage must also not exceed this value, so that in the known circuits the aforementioned thyratrons may only be operated with forward voltages at the anode of 9 kV, although maximum forward voltages of 40 kV would be admissible according to the manufacturer.